1. Field of the Invention
The present invention relates to a bump used for establishing electric contact with an electric part, a probe card that the bump is formed on a conductor, and to a method of forming such a bump. In particular, the present invention relates to a bump and a probe card that a conductive material is fused to or moltenly formed on a conductor.
2. Description of the Related Art
In the February 1996 edition of the magazine Nikkei Micro-Device is illustrated a shape of a bump used for keeping in contact with electric parts. Etching and a plating are among the methods used to form such a bump. However, the etching cannot provide all desired shapes. In addition, etching makes it difficult to form a bump accurately according to a specification, requires much time for forming, and has a high cost. Etching is therefore not suitable for mass production applications. Plating, meanwhile, can only provide a bump having a round peripheral portion.
Meanwhile, in the September 1997 edition (p. 168–169) of M & E published by Kogyotyosakai was shown a method of forming a bump by moving a soldering ball with a suction instrument. However, this method rounds the shape of the bump when melting a solder, and desirable contact with the electric parts can not be obtained.
Japanese patent publication 2691875 by Okubo et al., registered on Dec. 17, 1997 and published on Aug. 30, 1996, discloses a method of forming a bump using a ball, a melted tip of a wire. This method is also taught in the Semiconductor Manufacturing Device Dictionary (Fourth edition, p. 290) edited by Nippon Handotai Seizosouchi Kyokai on Nov. 20, 1997. However, this method requires a number of steps for cutting the tip, and this method cannot make a plurality of bumps of a uniform height.